Stephen L. Olsen University of Hawaii PANIC-08 Nov 10-14, 2008 Eilat The XYZ mesons.

Stephen L. Olsen

University of Hawaii

PANIC-08 Nov 10-14, 2008 Eilat

The XYZ mesons

X & Y mesons

BaBar

BK +-J/

M(+-J/M(J)

X(3872)

BK J/

M(J/

Y(3940)

X(3940) X(4160)

e+e-DD*J/ e+e-D*D*J/

M(DD*) M(D*D*)

Y(4260)

Belle

Belle

Belle

Y(4

008

)?

e+e-ISR+-J/

Y(4350) & Y(4460)

e+e-ISR+-’

M(+-J/)

M(+-’)

e+e-ISRcc

M(cc)

M(J/

(Decay to finalstates with a ccpair & qi=0 )

BaBar

BaBar

Belle

Belle

Belle

Belle

Neutral cc X & Y mesons

Name JPC (MeV)

Decay modes Expts comment

X(3872)

1++ <2.3 J/ J/ DD* Belle/CDF/D0/BaBar DD*

molecule?

X(3940)

0?+ ~37 DD* (not DD, J/) Belle c’’(?)

Y(3940) ??+ ~30 J/ (not DD*) Belle/BaBar

X(4160)

0?+ ~140

D*D* (not DD, DD*)

Belle c’’(?)

Y(4008)

1-- ~225

J/ Belle

Y(4260)

1-- ~80 J(not’) BaBar/CLEO/Belle

ccg hybrid?

Y(4350)

1-- ~75 ’ (not J/) BaBar/Belle

Y(4660)

1-- ~50 ’; cc (?) Belle @cc threshold

predicted

measured

Are any of these standard cc charmonium?

3872MeV

??

Is the 1++ X(3872) the c1’ (23P1) ?

• Mass is too low• c1’J/ violates Ispin

•Bf(X3872J/)>4%

• (J/) should be >>(J/)•expt: (J/) <<(J/)


Name JPC (MeV)


X(3872)


molecule?

X(3940)

0?+ ~37 DD* (not DD, J/) Belle c’’(?)


X(4160)

0?+ ~140

D*D* (not DD) Belle c’’(?)

Y(4008)

1-- ~225

J/ Belle

Y(4260)

1-- ~80 J BaBar/CLEO/Belle

ccg hybrid?

Y(4350)

1-- ~75 ’ BaBar/Belle

Y(4660)


It is pretty widely --but not universally-- accepted that the X(3872) is not a standard cc charmonium state. For a dissenting view, see

C Meng & KT Chao PRD 75,114002 (2007)

Could the Y(3940) be charmonium?

Bf(BKY3940)xBf(Y3940J/) (MeV)

Belle (7.1 ± 3.1) x 10-5 87±34

BaBar (4.9 ± 1.1) x 10-5 33±12

Avg (5.2 ± 1.0) x 10-5 39±11

assuming Bf(BKY3940)<Bf(BKJ/) = 1.0x10-3

(Y3940J/)>1MeV

True for all other

BK(cc) transitions

>10x higher than any

measured cc hadronic transition


Name JPC (MeV)


X(3872)


molecule?

X(3940)

0?+ ~37 DD* (not DD, J/) Belle c’’(?)


X(4160)

0?+ ~140


Y(4008)

1-- ~225

J/ Belle

Y(4260)


ccg hybrid?

Y(4350)


Y(4660)


X(3940) & X(4160) = c” &/or

c’’’ ?

3940MeV4160MeV

One, or the other, could be the c”, but it seems veryunlikely that one is the c” and the other is the c’’’

c”

c’’’


Name JPC (MeV)


X(3872)


molecule?

X(3940)

0?+ ~37 DD* (not DD, J/) Belle c’’(?)


X(4160)

0?+ ~140


Y(4008)

1-- ~225

J/ Belle

Y(4260)


ccg hybrid?

Y(4350)


Y(4660)


?????

?????

1-- ISR Y states not seen in D(*)D(*)

D*D*

DD*

(4

040)

(4

160)

Y(4

008)

(4

415)

Y(4

660)

Y(4

260)

Y(4

350)

DD

DDπ

Λc+Λc

–

?

σ(e+e–→open charm)

NEW

(3

770)

if Ruds=2.285±0.03

Durham Data Base

Y(4

008)

(4

040)

(4

160)

Y(4

260)

Y(4

350)

(4

415)

Y(4

660)

Belle: Sum of all measured exclusive contributions

This means that the ISR Y stateshave (J/(’)) > 1 MeV

PRD 77, 01103

PRL 98,092001

PRL 100,062001

PRL 101,172001

G.Pakhlova et al (Belle):

Too large for charmonium

only 1 unassigned 1-- cc slot


Name JPC (MeV)


X(3872)


molecule?

X(3940)

0?+ ~37 DD* (not DD, J/) Belle c’’(?)


X(4160)

0?+ ~140


Y(4008)

1-- ~225

J/ Belle

Y(4260)


ccg hybrid?

Y(4350)


Y(4660)


?????

?????

?????

At most 1 of the 1-- Y states can be conventional cc charmonium

The Z mesons

Electrically charged counterparts

of the X & Y mesons

The Z meson candidates

M(

±’)

GeV

BK +’

Z(4430)

M2 (±

’)

GeV

2

M2(’) GeV2

M(

± c

1)

GeV

BK +c1

M2(’) GeV2

M2 (±

’c1)

GeV

2Z1(4050)

Z2(4250)

6.5

>6

R.Mizuk,R.Chistov et al (Belle) PRD 78, 072004

S.-K. Choi et al (Belle) PRl 100, 142001

Z meson propertiesName Mass(MeV) Width(MeV

)Decay mode

Z(4430) 4433±5 45+35-18 +’

Z1(4050)

4051+24-43 82+51

-29 +c1

Z2(4250)

4248+185-45 177+320

-72 +c1

Can’t be cc charmonium

minimal quark content:

ccud

d cuc

Still controversial

Arafat Gabareen Mokhtar

talk at ICHEP-2008

Z(4430) not confirmed by BaBar(but neither do they rule it out).

B.Aubert et al (BaBar) arXiv/0811.0564

BaBar

Belle

A full Dalitz-plot analysis of th

e Belle BK+’ data

will be reported at next m

onth’s QWG meeting in Nara

What could theyXYZ states be?

suggested possibilities(some references in backup slides)

c

u

cu

πc

u

c

uu

cu

ccu

π cuc u

cuucc u

cc

gc

cc

g

D(*)D(*) molecules(real or virtual)

masses should be nearM(D(*))+M(D(*)) massthresholds

Favored model for X3872

M(D0)+M(D*0)=3871.8±0.4M(X3872)=3871.4±0.4

diquark-diantiquarks

Expect SU(3) multiplets

cc-gluon hybrids

LQCD: M>~4.3 GeV

Open charm thresh=MD+MD** 4285(above Y4260 peak)

Non-zero chargesare not allowed

Thresholds

some of the states are near thresholds,but this is not a universal feature

DSDSD(*)D(*) (*) (*)

??

No exchng for DSDS

no evidence for multiplet partners

uccu

dccd

dccu

uccd

Xu(3872) Xd(3872) X+(3872) X-(3872)

Expect:

Bf(B0K-X+)Bf(X+J/)

Bf(B-K-X0)Bf(X+J/)

B+K-Xu B0K0Xd

M(Xd)-M(Xu)= 2(md-mu)/cos

L Maiani et al PRD 71,014028 (20050

8 ± 3 MeV

≈ 2

diquark-diantiquark expectations:

no X±(3872) isospin partner is seen

B0 K± ∓ 0J/ B∓ KS ∓ 0J/

Bf(B0K-X+)Bf(X++0J/)

Bf(B-K-X0)Bf(X++-J/)< 0.4

(expect 2)

? ?

B. Aubert et al (BaBar) PRD 71, 031501

BaBar BaBar

B0KSXd & BK±Xu with Xu=Xd?

M = 0.22 ± 0.90 ± 0.27 MeV

Compared to 8±3 MeV(Maiani et al PRD 71 014028)

BaBar, arXiv: 0803.2838

KS mode

K± mode

KS mode

K± mode

M = 2.7 ± 1.6 ± 0.4 MeV

Belle

Belle

BaBar

BaBar

What about in the X3872DD* channel?

PRL 97,162002,2006

B K D0D00

6.4σ

PRD77,011102,2008

B+& B0 D0D*0K4.9σ

NEW

347fb-1

M=3875.2±0.7 +0.9

-1.8

~2 higher thanM in J/ mode

M=3875.1 +0.7

±0.5-0.5

~4 higher thanM in J/ mode

Is this Maiani et al’spartner particle?

New results on X3872DD* from Belle

B K D0D*0

605 fb-1

D*→Dγ

D*→D0π0 Preliminary

Flatte vs BW similar result: 8.8σ

M=3872.6 +0.5

±0.4 MeV-0.4

Agrees with M

from J

/ mode

N.Zwahlen, T.Aushev et al (Belle) arXiv/0810.0358

More details inTagir Aushev’s talk

@ this meeting

How about cc-gluon hybrids?

c c

• qq-gluon excitations predicted 30 yrs ago • LQCD: lowest 1-- cc-gluon mass ~4.3 GeV

- QCD sum rules get lower values ~3.7 GeV

• relevant open charm threshold is D**D (~4.28 GeV) • (J/) larger than that for normal charmonium • (e+e-) for 1-- states less than ordinary charmonium

Horn & Mandula PRD 17, 898 (1977)

Banner et al, PRD 56, 7039 (1997); Mei & Luo, IJMPA 18, 15713 (2003)

Isgur, Koloski & Paton PRL 54, 869 (1985)

McNeile, Michael & Pennanen PRD 65, 094505 (2002)

Close & Page NP B443, 233 (1995)

Kisslinger et al, arXiv 0805.1943 (2008)

Y(4260) s

eems t

o matc

h all

of these

!!!

3.85-

3.88-

4.28-

4.36-

DD

D

D

D DD

4.66-

4285

DD** thresholds and the Y(4260), Y(4360) & Y(4660)

4.26-

Y(4360) & Y(4660) well above allDD** thresholds

Belle

Scoreboard

candidate

Molecule?

cq cq cc-gluon

X(3872)

X(3940)

Y(3940)

X(4160)

Y(4008)

Y(4260)

Y(4350)

Y(4660)

Z(4430)

Z1(4050)

Z2(4250)

??

??

??

??

??

??

??

??

??

??

??

No model can accommodate all

Are there XYZ counterparts in the b- and s-quark

sectors?

Y(4260) equivalent with b-quarks?

(e+e- (nS))

Peaks not consistent with known bb states

((nS) ~ 1000x too large for bottomonium

K.F. Chen et al (Belle) arXiv:0808.2445

Belle

Y(4260) equivalent with s-quarks?

(e+e- (1020))

Y(2175)f0(980)

e+e- f0(980)

M(f0(980)

f0(980)+-

BaBar

Confirmed by BES & Belle

confirmed by BESIIin J/ f0(980)

M(f0(980) GeV

M.Ablikim et al (BES)PRL 100, 102003 (2008)

X.L. Wang et al (Belle) arXiv: 0808.0006

(e+e- f(1020))

BelleBES

Maybe the X(1835) is one too?

M. Ablikim et al (BESII), Phys.Rev.Lett.95:262001,2005

J/X(1835) | ’

X(1835)

mostly ss

BES

Concluding remarks• A number of “mysterious” mesons have been

observed

• They have large hadron-charmonium partial widths– Much larger than those seen in the charmonium system

• There is no strong variations above DD** thresholds – As expected for cc-gluon hybrids

• Some are near thresholds but not all– As expected for molecules, threshold cusps, etc.

• No Isospin or SU(3) multiplet partners yet seen– As expected for diquark-diantiquark models

• Similar structures in b- & (maybe) s-quark sectors

However, none of the proposed models have produceda compelling match to the experimental observations

Lots of pieces

Y(4360)

Y(4

660)

Y(4260)

Y(4

008)

X(3872)

X(3940

)

X(416

0

)

Z(4430) Y(3940)

Are the

y al

l fro

m the

sam

e pu

zzle

?

Thank you

Backup Slides

Some recent reviews

• Galina Pakhlova arXix:0810.4114– This includes 64 references– See slides from her plenary talk @ ICHEP08

• S.-K. Choi arXiv:0810:3546– See slides from her parallel talk @ ICHEP08

• E. Braaten arXiv:0808.2948– 48 references, mostly on molecular-like models

• S. Godfrey & S.L.O. arXix:0801.3867– 128 references, but almost a year old

Some theory references

cc

c1’ charmonium?

•C Meng & KT Chao PRD 75,114002 (2007)

•NA Tornqvist PLB 590, 209 (2004)•ES Swanson PLB 598,197 (2004)•E Braaten & T Kusunoki PRD 69 074005 (2004)•CY Wong PRC 69, 055202 (2004)•MB Voloshin PLB 579, 316 (2004)•F Close & P Page PLB 578,119 (2004)…

•L Maiani et al PRD 71,014028 (2005)•T-W Chiu & TH Hsieh PRD 73, 111503 (2006)•D Ebert et al PLB 634, 214 (2006)•H Lipkin & M Karliner PLB 638, 221 (2006)…

too light?? P Lacock et al (UKQCD) PLB 401, 308 (1997)

B-factories produce lots of cc pairs

0-+, 1- - or 1++

0-+, 0++, 2++

C =+ states

1- - only

Stephen L. Olsen University of Hawaii PANIC-08 Nov 10-14, 2008 Eilat The XYZ mesons.

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